I agree ^^.
I have seen many tanks with a single angel where the angel looks quite healthy and active and stress-free. Of course in the wild, they do tend to group with others of their species, but they are not a schooling fish of the type that will waste away and not thrive if they are kept alone. They can certainly thrive without another angel present, and I can guarantee you that they are neither 'lonely' nor 'depressed' LOL. I have a friend who had a single angel doing well in her 55G tank, and decided to add another as a 'friend' because her angel was 'lonely'. Well, the original angel decided it didn't like her choice of 'friend' and picked on the poor new guy until she had to get rid of him. The angel's back by himself, and seems not to miss his old tankmate one bit.
ok ok so i'm glad that my choice of word "lonely" is serving up much hilarity for everyone.
that being said, i think this post is actually the most helpful. i want an angel to thrive, i want all of my fish to thrive and be under as optimal conditions as possible. and i do believe that fish have emotional lives, even if others think this is hilarious. it used to be hilarious that monkeys, gorillas, dogs, dolphins, pigs etc had emotional lives. i truly believe that if someone wants to argue the side of "it's not the same as us" is negating emotional lives of other species. i won't assume that refusing to eat and dying at the foot of your dead child as many species have been known to do is not grieving and i won't discount the need for all animals be they "food" or "pets" to be given the benefit of the doubt that they need a positive emotional experience.